Fish tape



A ril 3, 1962 w. SPARKS FISH TAPE Filed 001;. e, 1959 W/ ///0/77 p ar/wIN V EN TOR.

ATTORNEY) This invention relates to a tool for pulling cable or the likethrough a conduit. In one of its novel aspects, it relates to a fishtape which is so constructed to be flexible in different planes. Inanother of its novel aspects, it relates to a fish tape that is guidedand supported in a conduit on spaced sleds or runners to provide foreasy insertion and pulling of the tape through the conduit.

In the electrical industry and other industries, it is frequentlynecessary to pass cable or similar material through a conduit which maybe laid in the walls, floors and ceilings of buildings or buried in theground. The conduit may be of substantial length and may be bent orcurved in different planes over its length. Usually it is not possibleto push the cable itself through the conduit because of limited space,lack of rigidity in the cable or other reasons; therefore, it is commonpractice to pull the cable through the conduit by use of a pullingmember, previously threaded through the conduit. Members used for thispurpose are known in the electric wiring art as fish ta es.

One type of fish tape known in the art comprises a metallic shaft ofsubstantially rectangular cross-section. While this rectangular fishtape is flexible about its major axis, it is virtually inflexible aboutits minor axis. Being flexible about a single axis, this fish tape isdifficult to insert and pull through a conduit that may bend in morethan one plane, particularly if the bends are relatively close together,since the tape must be twisted to expose its flexible axis to the newbending plane. In addition, a rectangular fish tape tends to ride alongthe conduit on its face or larger surface rather than its edge orsmaller surface. This situation can cause a great amount of frictionbetween the tape and conduit making it extremely difficult to insert andpull the tape through the conduit. The twisting action necessary tonegotiate bends in different planes further increases the friction andresistance to movement of the tape through the conduit. 7

Another type of fish tape known to the art comprises a two-piece fishtape having an inner pulling element and an outer housing, for example,a steel spring, for guiding and supporting the inner pulling element.Neither of these elements contributes substantially to the function ofthe other, that is, the housing does not have sufficient stiffness ortensile strength to contribute signficantly to threading through theconduit or to the pulling function of the inner element, and the innerelement does not contribute substantially to the guiding and supportingfunc-' tion of the housing during insertion of the tape through theconduit. This two-piece fish tape has other disadvantages andundesirable features. It is expensive to manufacture and diflicult toanchor the two elements together so that they will move as a unitthrough the conduit during the insertion operation and the pullingoperation. Since the pull on this type of fish tape is exerted primarilyon the inner element and the drag or friction is exerted primarilybetween the outer element and conduit, a high shearing force is createdbetween the inner and outer elements during the pulling operation. Thisshearing force in some cases may shear the anchor connection between theinner pulling element and outer housing thereby separating the tape intotwo parts. In addition, the friction between the housing and conduit isrelatively high since the housing is usually of substantially the sameconfiguration in cross section as the conduit, and

atet ii as a result a large portion of the outer face of the housingdrags on the conduit along its entire length. This friction between thehousing and conduit makes it diificult to insert the fish tape throughthe conduit and substantially increases the pulling force required topull the cable through the conduit.

An object of this invention is to provide a fish tape that will obviatethe above difiiculties and disadvantages.

Another object of this invention is to provide a fish tape that isflexible in different planes.

Another object of this invention is to provide a fish tape having a lowdegree of friction during the insertion and pulling of the fish tapethrough a conduit.

Another object of this invention is to provide a fish tape for pullingcable or similar material through a conduit that is so constructed so asto be easily inserted and pulled through a conduit which may be ofsubstantial length and which may have a number of bends in differentplanes along this length.

Another object of this invention is to provide a fish tape for pullingcable through a conduit, the fish tape being constructed of a pluralityof elements, each element contributing in a substantial degree to thecompressive strength or stiffness required to push the tape through theconduit and also contributing in a substantial degree to the tensilestrength required to pull a tape and cable throughthe conduit.

Another object of this invention is to provide a fish tape of the typedescribed in the above object which is so constructed that theindividual elements alternatively form sleds or runners at spacedintervals along the length of the tape for guiding and supporting thefish tape with a Eninixnum of friction during its passage through theconuit.

These and other objects and advantages are realized by the practice ofthis invention in the forms illustrated in the drawings wherein at leasttwo opposing pairs of elastically flexible elements are braided togetherto form a fish tape by crossing a first opposing pair of elementsbetween a second opposing pair of elements and then crossing the secondopposing pair of elements between the first opposing pair of elementsbefore re-crossing the first opposing pair of elements. The ends of theelements at each end of the fish tape may then be secured, as by weldingor crimping to a suitable eye or hook to provide a connection forattaching the fish tape to the cable on one end and to provide acoupling for a pulling device at the other end.

Such a fish tape has a series of spaced skids or runners approximatelyparallel to its longitudinal axis located at intervals around the faceof the tape and along its length. These provide points of contactbetween the fish tape and conduit at spaced intervals along the conduitto guide and support the fish tape when it is passed through theconduit. Inasmuch as the fish tape contacts the conduit only at spacedintervals along its length, the friction or resistance to movement ofthe fish tape through the conduit is greatly reduced. This reduction infriction provides for easy insertion of the fish tape through theconduit and also provides for easy pull of the cable and tape throughthe conduit. This arrangement also reduces the tendency of the fish tapeto spiral or twist as it is passed through the conduit.

It is intended that the term elastically flexible as used in thespecification and claims be taken to include all elements known to theart as being suitably flexible and elastic for the construction of afish tape according to this invention. For example, the elements may beof steel or plastic wire or filaments. In other applications, it may bedesirable to use insulated wire to protect the operator from hotcircuits in a fuse panel. In any event, the elastically flexibleelements used in the constructicn of the fish tape of this inventionshould be sufficiently flexible to negotiate the bends which may beencountered in the conduit, yet have sufficient compressive strength andstifiness to feed through the conduit without buckling or doubling backwhen inserted therein by an operator. In addition, the elements shouldhave sufficient tensile strength to pull a cable through the con dnit,even though a substantial force may be required to accomplish such apull.

The elements making up the opposing pairs may comprise a plurality ofstrands, the strands comprising each element preferably being taken as aunit and braided with other elements as above described to provide thefish tape of this invention. The number of strands comprising eachelement can vary, depending upon the particular application involved.For example, for a given total tensile strength to be provided by thefish tape, greater flexibility for negotiating bends in a conduit isgenerally provided by utilizing a plurality of relatively small strandsfor each element rather than a fewer number of larger strands for eachelement. On the other hand, because of the pres ence of other cable inthe conduit or other reasons, it may be desirable to provide a fish tapeof relatively high compressive strength or stiffness to permit the fishtape to be inserted through the crowded conduit. In this case, a smallernumber of relatively large strands in each element would be preferred.Other considerations can influence the number and size of strands to beused in a particular application.

In this connection, it will be understood that it is generallypreferable that the elements of opposing pairs comprise an equal numberof strands. Further, in some instances, it is desirable that thedifierent opposing pairs comprising the fish tape of this inventioninclude elements having an equal number of strands.

Referring now to the drawings wherein like characters are used todesignate like parts:

FIG. 1 is a perspective view of one embodiment of the fish tape of thisinvention being passed through a conduit, the conduit being shown asbent in difierent planes and the conduit broken away to show the spacedpoints of contact between the tape and conduit;

FIGS. 2 and 3 are plan views of the fish tape of FIG. 1;

FIG. 4 is a section taken along the fish tape of FIG. 2 at the line 4-4;

FIG. 5 is a section of the fish tape of FIG. 2 taken along line 55;

FIG. 6 is a section of the fish tape of FIG. 2 taken along line 6-6;

FIG. 7 is a section of the fish tape of FIG. 2 taken along line 77; and

FIG. 8 is a section of another embodiment of this invention wherein eachelement of one opposing pair includes two elastically flexible strands.

In a preferred embodiment of this invention, the crossing of elements ofopposing pairs, above referred to, is accomplished by sequentiallytwisting one opposing pair of elements in one direction intermediate thetwisting of another opposing pair of elements in the opposite direction,each element comprising an equal number of elastically flexible strands.

Referring now to the drawings wherein the above embodiment is shown, andfor reason of simplicity of illustration, each element is shown ascomprising a single elastically flexible strand, for example, steel wiresuch as piano wire, the fish tape indicated generally at 15 comprises abraided body member 16 fashioned by braiding together opposing pairs ofelements, one opposing pair being designated 17 and 17a, and the otheropposing pair being designated 18 and 1811. As can be seen from FIGS. 2through 7, the elements are braided together by twisting opposingelements 17 and 17a in one direction intermediate the twisting ofopposing elements 18 and 18a in the other direction. This sequentialtwisting of one opposing pair of elements in one direction intermediatethe twisting of the other opposing pair of elements in another directionis continued until a fish tape of the desired length is obtained. Theends of the elements at each end of the tape may then be secured, as bywelding, to a coupling 19 to provide a means of connecting the fish tapeat one end to the cable to be pulled through a conduit, and to provide ameans at the outer end for pulling the fish tape and cable through theconduit.

Although the elements in this embodiment are braided together bytwisting the opposing pairs of elements in opposite directions, it willbe understood that it is with-in the scope of this invention to braidthe elements together by crossing opposing pairs of elementsintermediate the crossing of other opposing pairs of elements withouttwisting the elements of opposing pairs together.

One important feature of this invention is the provision of spaced skidsor runners along the face of the braided body member for guiding andsupporting the body member when it is passed through a conduit. Thisfeature of the invention can be seen in FIG. 2 wherein the segmentalportions of elements 17 and 17a between their crossings 20 define suchskids or runners alternatively along the length of body member 16.Elements 18 and 18a define like skids or runners intermediate theircrossings 22, the skids or runners formed by elements 18 and 18a beingdisposed between the skids or runners of elements 17 and 17a and in aplane at an angle thereto. These skids or runners defined by theelements intermediate their crossings provide points of con tact betweenthe braided body member and the conduit at spaced intervals along thelength of the conduit (FIG. 1) when the fish tape is passed through theconduit. Thus, as distinguished from fish tapes presently known in theart, the fish tape of this invention is guided and supported in theconduit by relatively widely spaced skids or runners along the length ofthe fish tape. This reduction in overall area of contact between thefish tape and conduit substantially reduces the friction or resistanceto movement of the fish tape when it is passed through the conduit,thereby reducing the force required to insert the fish tape through theconduit and to subsequently pull the fish tape and attached cablethrough the conduit. In addition, it will be observed that the skids orrunners defined by the elements lie in planes substantially parallel tothe longitudinal axis of the braided body member, and

ence are directed toward, rather than across, the direction of movementof the fish tape when it is passed through a conduit. This arrangementfurther reduces the friction between the fish tape and conduit and alsoreduces the tendency of the fish tape to twist or spiral as it is movedthrough the conduit.

In the embodiment of FIG. 8, one opposing pair of elements, 23 and 24,comprise a plurality of strands, element 23 including strands 23a and23b, and element 24 including strands 24a and 24b. In this embodiment,opposing pairs of elements 23 and and 24 are braided together withopposing pairs of elements 25 and 25a, as above described, the strandsmaking up each element being taken as a unit in the braiding operation.

The operation and use of the fish tape of this invention is as follows.A fish tape of desired length, constructed, for example, according tothe foregoing embodiment, is threaded by pushing it through a conduit 21(FIG. 1) and a cable is attached to the coupling at the end of the fishtape. The fish tape and cable are then pulled through the conduit bypulling on the coupling at the other end of the fish tape. Inasmuch asthe braided body member of the fish tape of this invention isapproximately equally flexible in all different planes, the fish tapemay be inserted through the conduit without the necessary of twistingthe fish tape to expose a flexible axis to bends in the conduit, eventhough such bends may be in dilferent planes and relatively closetogether. Further, each element comprising the fish tape of thisinvention not only forms skids for guiding and supporting the fish tapewhen it is passed through a conduit, but also contributes in asubstantial degree to the required compressive strength or stiffness forinserting the fish tape through the conduit, and to the required tensilestrength for pulling the fish tape and cable through the conduit.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed with out reference to other features andsubcombinations. This iscontemplated by and is Within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

l. A fish tape for pulling cable or the like through a conduit,comprising, a plurality of opposing pairs of elastically flexibleelements braided together, the braided elements being flexible indifferent planes and defining alternate skids spaced along the length ofthe tape to provide spaced points of contact between the fish tape andconduit for guiding and supporting the fish tape when it is passedthrough a conduit, said braided elastically flexible elements beingcontiguous along the length of said tape and having suflicient strengthin compression to avoid buckling While being pushed through a conduitand sufficient strength in tension to pull a cable therethrough withoutsubstantial change in cross-sectional area of the tape and connectingmeans mounted on said elastically flexible elements for connecting saidcable to said elements.

2. A fish tape for pulling a cable or the like through a conduit,comprising, a body member, said body member including at least two pairsof crossed opposing elements braided together, one pair of opposingelements being crossed intermediate the crossing of the other pair ofopposing elements whereby the elements in each opposing pair of elementsdefined skids, each skid having a smooth continuous surface extendingapproximately longitudinally along the face of said body memberintermediate the crossings of said opposing elements for contacting aconduit at spaced intervals along the conduit to guide and support thebody member when it is inserted through the conduit, said elements beingof an elastically flexible nature and having sufficient strength incompression to avoid buckling while being inserted through a conduit andsuflicient strength in tension to pull a cable through the conduit, andconnecting means mounted on said body member for connecting the bodymember to the cable to be pulled through the conduit.

3. A fish tape for pulling cable or the like through a conduitcomprising, a body member bendable in ditferent planes, said body memberincluding at least two opposing pairs of elastically flexible elementsbraided tothe body member to the cable to be pulled through the conduit.

4. A fish tape according to claim 3 wherein at least one of saidelements comprises a plurality of elastically flexible strands.

5. A fish tape according to claim 3 wherein each element of at least oneof said opposing pair of elements comprises a plurality of elasticallyflexible strands, each element of said opposing pair of elements havingan equal number of said elastically flexible strands.

6. A fish tape according to claim 3 wherein each of said elementscomprises at least one elastically fiexible strand, each of the elementshaving an equal number of said elastically flexible strands.

7. A fish tape for pulling cable or the like through a conduit,comprising, in combination, a braided body member, a coupling mounted oneach end of the body member, said braided body member includingelastically flexible means bendable in different planes for guiding andsupporting the braided body member when it is passed through a conduit,said elastically flexible means having sufiicient strength incompression to avoid buckling while being inserted longitudinallythrough the conduit from one end thereof and sutficient strength intension to pull a cable through the conduit, said elastically flexiblemeans including at least two pairs of mutually twisted opposingelastically flexible Wires connected at the ends thereof to saidcouplings and being braided together intermediate said couplings, onepair of wires being twisted about each other in one directionintermediate the twisting of another pair of wires about each other inthe other direction whereby the segmental portions of each pair of wiresintermediate the crossings of such pair of wires define alternate skidsalong the face of the braided body member for contacting the conduit atspaced points along the conduit to provide said guiding and supportingof the braided body member when it is passed through the conduit, saidskids having smooth longitudinally extending skid surfaces and beingsubstantially parallel to the longitudinal axis of said braided bodymember.

References Cited in the file of this patent UNITED STATES PATENTS832,343 Scott Oct. 2, 1906 1,020,672 Wilson Mar. 19, 1912 1,475,859Nyman Nov. 27, 1923 2,142,641 Garris Ian. 3, 1939 2,750,152 SchinskeJune 12, 1956

